Submission #733435

#	Time	Username	Problem	Language	Result	Execution time	Memory
733435		rainboy	비용 (KOI11_cost)	C11	24 / 24	46 ms	4276 KiB

cost

#include <stdio.h>
#include <string.h>

#define N	100000
#define M	100000
#define MD	1000000000

unsigned int X = 12345;

int rand_() {
	return (X *= 3) >> 1;
}

int ii[M], jj[M], ww[M];

void sort(int *hh, int l, int r) {
	while (l < r) {
		int i = l, j = l, k = r, h = hh[l + rand_() % (r - l)], tmp;

		while (j < k)
			if (ww[hh[j]] == ww[h])
				j++;
			else if (ww[hh[j]] < ww[h]) {
				tmp = hh[i], hh[i] = hh[j], hh[j] = tmp;
				i++, j++;
			} else {
				k--;
				tmp = hh[j], hh[j] = hh[k], hh[k] = tmp;
			}
		sort(hh, l, i);
		l = k;
	}
}

int ds[N], sz[N];

int find(int i) {
	return ds[i] < 0 ? i : (ds[i] = find(ds[i]));
}

int join(int i, int j) {
	int s;

	i = find(i);
	j = find(j);
	if (i == j)
		return 0;
	s = (long long) sz[i] * sz[j] % MD;
	if (ds[i] > ds[j])
		ds[i] = j, sz[j] += sz[i];
	else {
		if (ds[i] == ds[j])
			ds[i]--;
		ds[j] = i, sz[i] += sz[j];
	}
	return s;
}

int main() {
	static int hh[M];
	int n, m, h, h_, i, sum, ans;

	scanf("%d%d", &n, &m);
	sum = 0;
	for (h = 0; h < m; h++) {
		scanf("%d%d%d", &ii[h], &jj[h], &ww[h]), ii[h]--, jj[h]--;
		sum = (sum + ww[h]) % MD;
		hh[h] = h;
	}
	sort(hh, 0, m);
	memset(ds, -1, n * sizeof *ds);
	for (i = 0; i < n; i++)
		sz[i] = 1;
	ans = 0;
	for (h = m - 1; h >= 0; h--) {
		h_ = hh[h];
		ans = (ans + (long long) sum * join(ii[h_], jj[h_])) % MD;
		sum = (sum - ww[h_] + MD) % MD;
	}
	printf("%d\n", ans);
	return 0;
}

Compilation message (stderr)

cost.c: In function 'main':
cost.c:63:2: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |  scanf("%d%d", &n, &m);
      |  ^~~~~~~~~~~~~~~~~~~~~
cost.c:66:3: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |   scanf("%d%d%d", &ii[h], &jj[h], &ww[h]), ii[h]--, jj[h]--;
      |   ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 4.8 / 4.8
• Subtask 2: 7.2 / 7.2
• Subtask 3: 12 / 12